How do you recommend I overlay textures on object 'Faces'
First of all, import images as planes creates a new mesh, dimension as the image of your choice, unwrapped and with the texture applied: it's not what you're looking for, you want to apply a texture to your already prepared mesh.

There are many approach to this task:

In your case I would go like this:

Numpad 7 and toggle 5 to get orthographic top view,
select all horizontal faces,  U to unwrap, project from view, rename the UV map as something like "UV Top view".

Then H for hiding already unwrapped faces (Alt H to return to whole mesh)

Numpad 1 to front ortographic view, select vertical and visible faces, create new UV map (plus sign), rename it as "UV front view",  U to unwrap, project from view, and so on .....

Then choose different UV maps for every part of the mesh when texturing.

The concept is to create different UV maps mapping useful portion of your mesh in the most useful way. It's good to have a single UV map only if you want a seamless texture over the whole mesh, but I think you're not going to use the same texture on walls, floors and ceilings!

Then we can think about the floor as example of workflow:

Set a new material for floor, set your images textures (even with bump, spec, ...) select all floor faces, in the UV editor window select all and S - scale the "top view" UV map as desired scale (i'm assuming everything is tileable); in the Image editor you can use S X to scale the UV map along the horizontal axe, and S Y in the vertical one, to achieve the desired overall scale and minimum stretching of the texture.

You will have to specify to all your textures the correct UV map.

It's more difficult to say in words than do it: experiment it with a simple mesh and a couple of textures.